Process of treating solid fuels



' chloride, kerosene, etc., have particularly with reference to Patented Apr. 6, 1937 UNITED STATES 2,076,497 PROCESS OF TREATING SOLID FUELS Carleton Ellis,

Montclair, N. J., assignor to Standard Oil Development Company, a

corporation of Delaware Application December 29, 1931,

No Drawing.

Serial No. 583,705

6 Claims.

Solid fuels such as coal and coke in a lump or fragmental form which in handling'through various producing and marketing channels tend to produce particles of dust-like fineness, possess the disadvantage of dusting which often is objectionable to the consumer. j

In accordance with the present invention such solid fuels are rendered substantially non-dusting by waxing with a substantially odorless waxy material of the class including paraflin wax, ceresin wax, and more particularly high molecular weight soft amorphous waxy bodies such as those constituting commercial grades of petrolatum, as well also as certain wax-containing heavy petroleum distillates, such as the so-called slop-end from Palembang crude oil.

In treating coal to prevent dusting by applying a coating of a petroleum oil, such as kerosene, the objection arises that a large body of such coal stored for example in the basement of a house imparts an odor to the building which is objectionable. Waxes obtained from petroleum normally are free from odor. This is particularly true of petrolatum which may be regarded as odorless and which, moreover, is derived in large quantities in the refining of petroleum oils, hence is abundant and cheap.

The invention therefore will be described more the employment of petrolatum or similar soft amorphous mineral waxy materials, using as the preferred solid fuel lu'mp coal (bituminous and anthracite). This lump coal may be the usual sizes now on the market, ranging from the pea and nut sizes to egg and furnace coal, and the like. However, .it should be understood by the term coal I propose to include other solid fuels such as coke and the like, which have dusting tendencies which are wholly or largely suppressed in accordance with the practice of the present invention.

While various substances such as calcium been proposed for treatment of coal to prevent dusting, most of these are not of a character which increases the fuel value or if such increase did take place disagreeable odors may result; whereas the treat-' ment of coal with petrolatum to make a petrolatumized coal increases the ent upon the proportion of petrolatum employed, and does not cause the fuel in the storage bins to give off objectionable o'dors. There is furthermore 'no difficulty with corrosion, which is encountered when using calcium chloride or the like.

With respect, however, to the proportion of fuel value, dependpetrolatum, it is desirable to keep the amount below that which would of itself cause a smoky black flame to result on firing. Since only a relatively small proportion of petrolatum, this varying with the size of the lumps of coal, is re- 5 quired to prevent dusting, I find it possible to keep the proportion preferably well below the point of such objectionable black smoke formation while at the same time having present enough of this petroleum material to keep dust v1O from contaminating the air in any objectionable degree while the coal issubiected to the usual handling in the household or elsewhere as, for example, when the coal is being discharged through chutes into the coal bins or is being 15 transferred from bin to furnace. Another "point which is somewhat advantageous' is the'fact that the coating of petrolatum on the coal tends to deepen the color, giving the coal a cleaner, blacker appearance whilecement- 0 ing to the surface of the lumps fine particles of coal which otherwise would be lost in the form of dust. At the same time it is'possible to incorporate .with the petrolatum asuitable pigment whereby the coal can be given'any appropriate color desired. In this event it is preferable to employ pigments which do not furnish bodies that cause clinkering by lowering the fusion point of the ash. Thus, for example, a coal having'a high silica ash desirably is not pigmented with an iron oxide, chromium oxide, or other pigment which increases the ease of fluxing of the ash, for if such pigment is present in any substantial proportion a non-clinkering coal might then become clinkering to an objectionable degree. A petrolatumized pigmented coal, but one which preferably is not pigmented with clinker forming pigments, falls'within the scope of the present invention. p

, It should be noted that the petrolatumized coal 40 may be expected to possess greater ease of ignition in view of the fact-that the particles of the coal carry a coating of the petrolatum which may be looked upon as an odorless combustion assistant.

The petrolatum, or other form of wax, may be applied to the coal in the form of an emulsion as, for example, dispersed in water with the aid of a suitable emulsifying agent. This emulsion may be sprayed upon the coal at any suitable stage in the operations of handling and marketing the fuel.

The preferred method of procedure in accord-- ance with the present invention is to render petrolatum thoroughly liquid by heating and 9 latum flows while 5 I found it possible to spray it by means of a jet of a compressed gas or steam but preferably air, the spray being directed upon the lumps of coal as they are moving along some chute, but preferably at the rotary sizing screens. Using coal of nut size I have found, for example, that /2 gallon to 2 gallons of petrolatum to the ton of coal suffices to give a satisfactory coating, this proportion as noted will vary with the size of the coal as well as with other requirements. For ease of. handling by spraying the petrolatum may be melted in a tank and forced by the application of suitable pressure or the use of pumps to the spray nozzle where it is disseminated over the stream of coal moving along within the spray zone. In cold weather the usual type of equipment for handling substances which congeal when cold may be used, this being a concentric piping arrangement through the-inner pipe of which the petrosteam is passed through the outer passageway or amiulus.

While it might beexpected that spraying petrolatum with air would be hazardous owing to the supposed explosive character of such a mixture,

spray the petrolatum advantageously using an excess of air in-order that the mixture does not form an explosive combustion within the explosive range of petrolatum. Using air in this manner I have projected a spray which seemingly is richin petrolatum into the flame of a Bunsen burner without being able to ignite the spray jet. I therefore consider that it is entirely feasible to employ air as the spraying medium without involving the hazard of explosion.

The foregoing invention may be practised in the the. like.In the foregoing I have referredto the black smoke point ascribable to an excess of petrolatum and I do not wish to confuse this condition with the black smoke due to the employment of normally smoky fuels such as bituminous coal. Whenever the black smoke point is re- .ferred to herein it is understood that the fuel initself is substantially smokeless, as for example anthracite coal.

Also I have referred to the employment of emulsionsin the waxing of coal. For example, emulsions may be prepared from petrolatum, water and-an emulsifying agent such as ammonium linoleate, triethanolamine stearate (or linoleate), glycol stearate types, and the like. Sulphonates derived from acid sludge may be used as emulsifying agents or assistants. Emulsions also may, if desired, contain volatile solvents of petrolatum such as naphtha, carbon tetrachloride, dichlorand trichlor-ethylene. These additions to petrolatum alone or to its emulsions cent or less of a pour inhibitor such as that obtained by reaction bespraying the thus heated ized spray onto the fuel tween chlorinated paraffin wax and naphthalene in presence of aluminum chloride. This will serve to reduce the pour point and thus permit better distribution of the petrolatum spray over the surface of the lumps of coal.

In addition to the improved appearance of the coal resulting from the coating of petrolatum, I call attention to the possible cushioning effect of the surface layer of the waxed product which would tend to decrease fining. Any improvement in water resistance due to the waxy coating also may be expected to be helpful in retarding spalling and fining. Moisture which otherwise would penetrate fine cracks in coal lumps and on freezing tend to increase the size of the cracks with consequent disintegration is hindered by the petrolatum film from ingress and the integrity of the lump thus better preserved.

- What I claim is:

1. The process of treating solid lump fuel with heavy hydrocarbon oil of a viscosity too high to besprayed in a fine mist at ordinary temperatures, consisting of heating the oil sufficiently to fiuidize the same and to allow spraying, and then oil in'a finely atomized spray onto the fuel in quantity sufficient to deposit on said fuel a thin film of said oil.

2. The process of treating solid lump fuel with heavy hydrocarbon oil of a viscosity too high to be sprayed in a fine mist at ordinary temperatures, consisting of heating the oil sufiiciently to fiuidize the same and to allow spraying, then spraying the thus heated oil in a finely atomized spray onto the fuel in quantity sufficient to deposit on said fuel a thin enveloping film of said oil, and agitating the fuel'while spraying.

3. The process of treating fuel tending to form dust on handling or storage, comprising heating petrolatum sufliciently to fiuidize the same and to allow spraying, and then spraying the heated petrolatum in a finely atomized condition upon the fuel in quantities sufficient to prevent dustmg.

4. The process of treating solid lump fuel with petrolatum of a viscosity too high to be sprayed in ing the thus heated petrolatum in a finely atomin quantity suflicient to deposit on said fuel a thin film of said petrolatum.

5. Process according to claim 4, in which the fuel is agitated while being sprayed.

6. Process of coating coal which comprises projecting against lumps of coal in motion, a spray of molten petrolatum propelled by a jet of com-- pressed air; the air present in the spray zone being suincient to bring the spray mixture of petrolatum and air outside the explosive range: whereby a substantially noninfiammable condition of spray operation results.

CARLETON ELLIS. 

